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Zooplankton, the living tiny animals in water, are an important component of freshwater food webs, sustaining many freshwater fisheries. It has long been thought that a substantial portion of zooplankton diets come originally from land-based ecosystems, for example from nutrients leaching out of plant matter falling into the water, rather than being based entirely from freshwater sources. Now, a bias has been demonstrated in a key hydrogen-based method used to estimate the land portion of zooplankton diets.

Adult salmon are well known to return to the lake or stream where they hatched, to spawn another generation of salmon. In many places, fisheries catch them in the ocean on the way back to spawning, but before it is possible to assign them to a particular population from a stream or lake. A new model now shows a way forward to disentangling catches that come from multiple salmon populations, using genetics and analysis of scales.

In a retrospective look back on his career, SAFS professor Tom Quinn reflects on the experiences that have shaped his outlook and his philosophy on science, teaching, and mentoring. His experiences have included driving past defunct vulture-topped nuclear reactors, and waking up with bear prints on the outside of the window above his bed in his cabin in Alaska, together with many years working in the field on the long-term studies (since the 1950s) at the University of Washington’s Bristol Bay field program focused on salmon.

Estimates of migration are important for understanding and managing natural populations. A statistic known as FST is often used as a measure of the amount of genetic difference expected for a given population size and migration rate. Equations that translate FST into estimates of migration exist but the underlying ideal assumptions often do not apply. Now a new model has been used to test which factors affect FST in a real life example based on Atlantic cod.

When large rivers discharge their water into the sea, this creates a plume of freshwater that is highly variable. A new study that attached tiny satellite tags to seabirds now shows that both shearwaters and murres prefer to forage in plumes created by the massive Columbia River. In particular, they prefer the boundary areas between freshwater and sea water, since this area is where zooplankton and prey fish species are most concentrated.

Genetic techniques are capable of finding the entire sequence (“genome”) of DNA letters (“base pairs”), and have recently been applied to completely sequence 61 unrelated rainbow trout and steelhead individuals. The study found that one in every 64 letters varied across the rainbow trout examined (with variability in more than 30 million locations), and that there were more than 4 million locations where the individual DNA letters differ substantially.

Native oysters on the Pacific coast were devastated by commercial overfishing in the 20th century and their recovery has been prevented by water pollution, habitat loss, and possibly ocean acidification. Efforts underway to restore these Olympia oysters rely on harnessing genetic variation among populations to pick the best suited oysters for restoration. Now a new study shows that, even when reared for two generations under the same laboratory conditions, differences among populations persist.

Coal mining is well known to have negative impacts on the quality of water in streams, and now new findings show that fish, invertebrates, and salamanders are badly affected by the resulting pollution. A synthesis demonstrated that animal numbers declined by more than half (53%), and species numbers declined by one third, in streams affected by coal mines. These impacts happened in spite of current federal statutes (the 1972 Clean Water Act and 1977 Surface Mining Control and Reclamation Act), and persisted even after cleanup efforts post-mining.

More than 80% of the world’s renewable electricity comes from hydropower generated from dams, but these dams impede upriver passage of fish, and potentially damage fish migrating downstream that pass through turbines or over slipways. A new toolset has now been developed that can better estimate injury and death rates from fish passing downstream, using the data from artificial “sensor fish” that mimic the passage of fish through turbines and slipways while collecting high-resolution data.

The Bering Sea has highly variable sea ice extent in winter, which can be used to tease out the effects of future climate change on marine animals such as seabirds. In a new study, SAFS professor George Hunt and coauthors examined how seabirds change location in years when sea ice melts earlier in the year. In these years, seabirds that feed far from land tend to come closer inshore, while seabirds that feed closer to shore move further offshore.

The School of Aquatic and Fishery Sciences is dedicated to sustaining healthy marine and freshwater environments. Our faculty conduct innovative research from the organism to the ecosystem scale, and are recognized leaders in aquatic biology, sustainable fisheries management and aquatic resource conservation.